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Name(s): _____________________________ _____________________________ _____________________________ _____________________________ Date: __________________ Grade: __________________ Course/Section: __________________ Properties of Nebulae Objectives: Students will examine images of a supernova and a planetary nebula to learn about differences
between the two astronomical phenomena. Checklist: □ □ □ □ □ □ Complete the pre-­‐lab quiz with your team. Compile a list of resources you expect to use in the lab. Work with your team to complete the lab exercises and activities. Record your results and mark which resources you used. Share and discuss your results with the rest of the class. Determine if your team’s answers are reasonable. Pre-­‐Lab Quiz 1. 2. 3. 4. Part 1: Supernovae 1. Explain the differences between Type Ia and core-­‐collapse supernovae. Be sure to include details about the progenitors as well as what is left after the supernova. 2. What type of supernova produced the Crab nebula? Does it have a compact object? If so, explain what it is. 3. A typical supernova releases 1044 Joules of energy within a few seconds. Compare this yield to how much energy the Sun will produce over its entire main sequence lifetime, assuming a constant luminosity of 3.8 x 1026 J/s and an age of 15 Gyr. Show your work. (Hint, keep track of your units.) 4. Using the RGB images of the Crab, draw a diagram of the Crab in the three separate bands and identify where the hydrogen is located. 5. What is the diameter of the Crab nebula along its longest axis? Give your answer in light years and km. Show your work. 6. If the supernova that produced the Crab was observed in 1054 A.D., find the expansion rate in km/s. Show your work. Part 2: Planetary Nebulae 1. How do planetary nebulae form? 2. Using the RGB images of the Ring nebula, draw a diagram of the Ring and identify where the hydrogen gas is located. 3. What is the diameter of the Ring nebula? Give your answer in light years and in km. Show your work. 4. Assuming that the white dwarf associated with the Ring nebula is located at the center and that the nebula has been expanding constantly at v=20 km/s, find the age of the nebula in years. Show your work. 5. A typical density of a nebula is n=1.7 x 10-­‐10 kg/km3. Find the mass of the nebula in solar units. Show your work. 6. If the progenitor star that created the Ring nebula was ~1.8 Mʘ, what percentage of its mass was ejected to create the Ring? 7. How much does the white dwarf at the center of the nebula weigh in solar units? How much more mass does it require to reach the Chandrasekhar limit? Part 3: Discussion 1. Review your diagrams and the images of the Crab and Ring nebulae. Explain what differences you see between the two nebulae and discuss how their formation may contribute to these differences. You should also compare their expansion velocities in your discussion. 2. Based on your knowledge of stellar evolution, what is the fate of our Sun? 3. Find how long a planetary nebula formed by the Sun would take to reach Earth's orbit assuming an expansion rate of 20 km/s. Show your work. 4. How long would it take the planetary nebula to expand outside of the solar system? Show your work and give your answer in years. (Note, the solar system is about 80 AU.) 5. If the Sun could supernova, how long would it take for the explosion to reach Earth's orbit? Assume the expansion speed you found in the Part 1 for the Crab. Show your work. 6. The Sun will move off of the main sequence in 5.42 Gyrs and start to move up the red giant track. It will reach the tip of the red giant track within 2.17 Gyrs, and its final radius will be 1.19 AU. Compare the time it would take this to happen with your answers for questions 4 and 5.